NL 50, Bottom 2 on Super Wet Board, counterfeited on river

[DogTriumph]

Villain is somewhat passive over about a hundred hands, running at ~30/10. Anyone like a turn raise considering the million draws out there? Also, do I have to call this river with 2nd pair given that every obvious draw missed? Any input would be appreciated.

PokerStars No-Limit Hold'em, $0.50 BB (6 handed) internettexasholdem.com (http://www.internettexasholdem.com)

saw flop|<font color="#C00000">saw showdown</font>

BB ($50)
UTG ($49.35)
MP ($53.60)
<font color="#C00000">CO ($89.30)</font>
<font color="#C00000">Hero ($83.70)</font>
SB ($57.50)

Preflop: Hero is Button with 8/images/graemlins/spade.gif, 7/images/graemlins/spade.gif.
<font color="#666666">2 folds</font>, CO calls $0.50, <font color="#CC3333">Hero raises to $2.5</font>, <font color="#666666">2 folds</font>, CO calls $2.

Flop: ($5.75) 7/images/graemlins/club.gif, T/images/graemlins/diamond.gif, 8/images/graemlins/club.gif <font color="#0000FF">(2 players)</font>
CO checks, <font color="#CC3333">Hero bets $4.15</font>, CO calls $4.15.

Turn: ($14.05) A/images/graemlins/diamond.gif <font color="#0000FF">(2 players)</font>
<font color="#CC3333">CO bets $9</font>, Hero calls $9.

River: ($32.05) A/images/graemlins/heart.gif <font color="#0000FF">(2 players)</font><font color="#CC3333">CO bets $15</font> Hero?

[sightless]

river is an easy fold.
I like the turn call too.